Variable propeller



June 18, 1935. F. M. KE NT.

VARIABLE PROPELLER Filed May 9, 1954 Patented June 18,1935

PATENTI OFFICE VARIABLE PROPELLER Forrest M. Kent, Spokane, Wash. 7 Application May 9, 1934, Serial No. 724,719

2 Claims.

My present invention relates to variable propellers and is an improvement over the device set forth in my copending patent application entitled fVariable pitch propellers, filed March 29, 1933, Serial No. 663,355, and also over the device embodied in my prior joint Patent No. 1,864,045, issued June 21, 1932 and entitled Variable speed propellers. The principal objects of my present invention are to provide means whereby the increase and decrease in the pitch of propeller blades is automatically caused by the pressure resistance of the water, or other medium, against the blades and is in direct proportion to the revolutions of the blades, and,

whereby a rapid increase is caused in the momentum of the conveyance to' which the device is attached.

With the above and other objects in view which will appear as the descriptionproceeds, the invention consists of the novel construction, adaptation, combination and arrangement of parts hereinafter described andclaimed. These objects are accomplished by devices illustrated in the accompanying drawing; wherein:--

Figure -1 is a view in side elevation showing the device connected to the lower portion of an outboard motor; Fig. 2 is an enlarged view in rear end elevation of the device; Fig. 3 isa fragmentary view in transverse vertical section takenv substantially on a broken line 33 of Fig. 6; Fig. 4 is a view in longitudinal vertical section taken on a broken line 4-4 of Fig. 2; Fig. 5 is a detail view in perspective of the hub block; Fig. 6 is aview inside elevation of the device and showingthe propeller bladepitch movement in dotted lines; and Fig. '7 is a detail view in perspective of the restraining collar.

Referring indetail to the drawing, the numeral 5 designatesthe lower portion of an outboard motor having a shaft 5 projecting rearwardly from its hub"por'tion. A bushing or sleeve 1 fits snugly onto said shaft and a hub block 8 fits snugly onto said sleeve. A-shear pin 9 passing through said block, sleeve and shaft, together with a nut III .on the rear end of the shaft, retain'said members securely in place. The forward end portion of the hub block ishollowed out by a chamber H which is closed by a plate l2.

The hub block 8 has two opposite flat sides l3 upon which are seated the two flat inner T- ends of propeller blades l5. Said .flatinner ends are pivotally held by opposite screw bolts l6 extending through holes 11 therein and threaded into the hub block where set screws l8 hold them in place. Screw pins l9 are threaded through the flat T-ends of .the propeller blades and pass loosely through arcuate slots 20 in the hub block with. their inner pin 5 ends projecting into the chamber ll. The arc- .uate slots are concentric with the screw bolts -l6 so that, when the T-ends of the propeller blades are pivotally moved they will move the screw bolts back and forth in the arcuate slots. Set screws 2| may project through the hub block into communication with each end. of the arcuate slots and into engageable relation with the screw pins whereby the pivotal movement of the propeller blades may be adjustably regulated as will be understood.

The inner pin ends of the two screw pins I9 extend through holes in eyelet bearings 22 that 'are secured to a restraining collar 23 that is mounted on the bushing 1- of the shaft 6 within the chamber II. A coiled spring 24 is also mounted on said bushing within the chamber and has one of its ends fixed .to the hub block 8. The other end of said spring maybe connected to the collar 23 onto one of the eyelets 25 22.- This'spring is so arranged and tensioned as to normally retain the propeller blades [5 at a low or reduced pitch as shown in dotted lines in Fig. 6 of the drawing. It will be understood that the foregoing described connection between the T-ends of the propeller blades and the collar 23, namely the screw pins l9 and eyelets 22 causes the propeller blades to pivotally move in unison.

Referring particularly to Fig. 2 in describing the operation of the device, it will be noted that the screw bolts it about which the propeller blades pivotally move are diametrically opposite each other with respect to the center of the hub block 8 and shaft 6. A line, such as the 40 broken line l-J, projected centrally through said screw bolts and shaft will therefore represent the axis about which the propeller blades pivotally move. This line will divide the respec tive propeller blades into diametrically opposite. major portions X and minor portions In other words, the two blades are eccentrically. mounted with respect to each other, andthis is a very important feature of the invention.

When the device rotates in a counter clock- Wise direction, as indicated by ,the direction arrow inFig. 2, the major portions X will be the leading portions of the blades and will engage the water in advance of the minor portions Y. A greater pressure resistance will therefore be ly automatic and in direct proportion to the increase in the revolutions of the propeller blades. In other words, an increase in the revolutions of the propeller blades causes a corresponding increase in pressure resistance against the leading major portions of the blades and a like increase in' the pitch of the blades. vThe pitch of the blades may thus be increased'from the minimum, as shown in dotted lines in Fig. 6, to the maximum as shown in full lines, and the spring 24 will cause the blades to return to their minimum pitch when the rotary movement of the blades ceases.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is:-

l. A variable propeller comprising a shaft, a hub block fixed on the shaft, said hub block having a hollow chamber, two opposite fiat sides, and an arcuate slot extending through each fiat side into the chamber, a pair of propeller blades having flat inner T-ends respectively seated on the two opposite sides of the block, pivotal connections that are diametrically opposite to each other and concentric with the arcuate slots connecting the T-ends of the propeller blades to the block in such position that the centers of the propeller blades are offset with respect to spring mounted on the shaft within the chamber and having one of its ends connected to the hub block and-its other end connected to the collar.

2. A yariable propeller comprising a shaft, a hub block fixed on the shaft and having a hollow chamber, two opposite flat sides, and an arcuate slot extending through each flat side into the chamber, a pair of propeller blades pivotally connected to the flat sides of the hub block in opposite offset relation to each other, screw pins respectively connected to the propeller blades and extending slidably through the arcuate slots into the chamber of the block, a collar mounted on the shaft within said chamber, a pair of opposite eyelet bearings pivotally connected to said collar, said screw pins extending through said eyelet bearings, and a coiled spring mounted on the shaft and having one of its ends connected to the hub block and its other end connected to the collar.

FORREST M; KENT. 

